1. Field of the Invention
The present invention relates to a hurricane simulation testing apparatus and more specifically to an apparatus for testing building structures such as doors, windows, storm panels, hurricane shutters and the like, under hurricane type conditions to measure the strength and integrity of the structures under such conditions.
2. Description of the Related Art
In many coastal areas and regions where the risk of hurricanes is prevalent, building codes require that various structures on houses and buildings be able to withstand hurricane type conditions within predetermined parameters. In particular, Dade County, Florida has recently revised it's building code in response to the devastation experienced as a result of hurricane Andrew. The Dade County building code, which is the most rigorous in the country and is recognized by most other counties and municipalities, sets forth specific standards for building structures such as aluminum garage doors, windows, storm panels and hurricane shutters. In accordance with the building code, these various structures must withstand certain hurricane type conditions under a series of tests including subjecting the structure to increments of pressure, cycling of pressure and an impact test.
Prior to the new building code, various specified structures were only required to be subject to certain pressure tests. Typically, this has been done using a pressure chamber which is essentially a room having four side walls, a floor, a ceiling and an interior chamber of significant volume. The structure to be tested is mounted, facing inwardly, in a window opening on one of the side walls. For instance, when testing a garage door using this type of system, it is necessary to mount the outside of the garage door facing in towards the interior chamber so that the outside of the door will be subjected to the pressure conditions. With the test structure mounted, a large volume of airflow is either introduced to the interior chamber to increase pressure or, alternatively, the air is evacuated to create a negative pressure.
Pursuant to the building code test requirements, the increments of pressure test requires subjecting the structure to various increments of pressure between 0 to 500 PSF, maintaining the pressure for 30 seconds at the maximum pressure. The cycling of pressure test requires subjecting the structure to rapid changes of pressure between 0 and a defined maximum pressure throughout a series of repetitions. For instance, it may be required to subject the structure to a rapid increase of pressure from 0-25 PSF, for 700 cycles, with each cycle being completed within 3 seconds. Next, the structure would be subject to 10 cycles between 0-35 PSF and thereafter 1 cycle between 0-65 PSF. The specific number of cycles and maximum pressure levels depend on the product being tested and the elevation above ground level at which the product is expected to be used.
The new building code now requires, in addition to the increments of pressure test and cycling of pressure test, an impact test, wherein the structure must be subject to impact by an 8 foot long 2".times.4", fired at the structure at a predetermined velocity. Under each of the tests, inductive displacement transducers are used to measure the deflection of the structure at various designated locations. The requirements of the new building code present several problems when using a conventional air pressure testing chamber to test a particular specimen structure. In particular, the new code requires that each cycle, in the cycling of pressure test, be completed within 3 seconds. The conventional air pressure chambers, having a significantly large volume, require very high volume pumps to complete cycling within the required 3 second limit. Further, pressure testing requires the test specimen to be mounted with the outside of the specimen facing inwardly towards the pressure chamber. Accordingly, the impact test, required by the new building code, cannot be performed on the test specimen while mounted to the chamber, as the outside of the specimen (e.g. garage door) is not accessible. Thus, to perform the impact test, it is required to remove the test specimen from the air pressure chamber and remount the test specimen on another support structure. When performing the various tests on a large number of products, this procedure can prove to be expensive, time consuming and impractical.
Accordingly, there is a need for a test apparatus specifically structured to subject various test specimens to hurricane type conditions as required by new building codes, wherein cycling of pressure and impact tests can be performed rapidly and efficiently.